Pneumatic energy cartridge



Jan. 11, 1966 c A. DAMM ETAL 3,223,335

PNEUMATIC ENERGY CARTRIDGE Filed Aug. 29, 1963 2 Sheets-Sheet l INVENTORS CARL Av DAMM L MOGIBONEY 2km Cwe CJL ATTORNEYS my, m an iwaamaaj RALPH F ig. 1

Jan. 11, 1966 c. A. DAMM ETAL 3,228,335

PNEUMATIC ENERGY CARTRIDGE Filed Aug. 29, 1963 2 Sheets-Sheet 2 F lg. 3

INVENTORS CARL A. DAMM RALPH L. McGlBONEY BYl ATTORNEYS United States Patent 3,223,385 PNEUMATI ENERGY CARTRIDGE Carl A. Dainrn, Upper Black Eddy, and Ralph L. lilo- Gibouey, Hathoro, Pa., assiguor to the United States of America as represented by the Secretary of the Navy Filed Aug. 29, 1963, Ser. No. 305,561 12 Claims. (Cl. 124-11) (Granted under Title 35, U8. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

This invention relates to a pneumatic energy cell for storing and automatically maintaining a large infinitely adjustable force capable of instantaneous release and more particularly to a pneumatic energy cell having the ability to recharge itself at a leisurely rate through mechanical actuation by a very small electric motor or by manual operation.

Some airborne stores or weapons such as torpedoes used in anti-submarine warfare are required to enter the Water at some specified angle. In order to obtain this entry angle or trajectory, the speed of the airborne carrier, its altitude, and the mass moment of inerita about the transverse horizontal axis through the center of gravity of the weapon are taken into consideration. These factors determine the amount of force necessary to be imparted to the weapon to achieve the required longitudinal turning moment or predetermined speed about the horizontal axis through the center of gravity of the weapon.

Present weapon launching systems and ejecting systems located aboard helicopters utilize an ejector consisting of a mechanical spring as the energy storing medium. A small hand operated winch is used to energize the spring, the winch being detachable so that only the charged ejector goes with the aircraft. This unit is limited to two different degrees of compression of the spring which thereby achieve only two different angular speeds or longitudinal turning moments from a weapon of a specific mass moment of inertia. Additionally, these spring ejectors have a low maximum ejecting force and therefore are placed a great distance forward of the center of gravity of the weapon in order to provide the weapon with the appropriate longitudinal turning moment about its center of gravity when it is ejected to thereby enter the water at the desired angle. In view of the great weight of the mechanical spring ejecting mechanism and in view of its placement a large distance forward of the center of gravity of the helicopter, it being understood that the center of gravity of the weapon coincides with the center of gravity of the helicopter, it is readily seen that a large pitching moment is applied to the helicopter which must be overcome.

A possibly more important objection to the present mechanical spring ejector is that since the spring unit is limited to two mechanical settings, only two longitudinal turning moments or angular speeds are available for a particular weapon. Therefore, the altitudes at which the drop is to be made and the ground speed of the helicopter are severely limited. Additionally, the presently utilized mechanical spring ejection mechanism causes delay in takeoff time due to the lapse of time taken in the winch operation.

The pneumatic-type ejectin mechanisms have been found to be extremely heavy and structurally complicated with attendant high procurement costs and have presented, particularly in helicopters, serious Weight problems since the margin of takeoff for the helicopter with a full load is border line. It being understood that the weapon or store is detachably connected to the helicopter by hooks,

straps, or the like, the timing sequence of release of the hooks or hands, and the subsequent actuation of the ejecting mechanism becomes highly critical and where release of the books or straps does not occur and the ejection force is actuated first, serious accideints have occurred. The timing sequence is particularly difficult to maintain with sustained accuracy in prior ejecting mechanisms.

It is an object of the present invention to provide an expandable metal bellows pneumatic ejector which is of light weight and which is capable of developing extreme high ejection forces.

An additional object of the invention is to provide a pneumatic ejector having an infinitely variable ejecting force capability which will thereby yield any angular speed or pitch or any longitulinal turning moment to a weapon.

Still an additional object of the present invention is to provide a pneumatic ejector which can be charged away from the aircraft and wherein the attachment to the aircraft can be effected in a relatively simple operation requiring a minimum of time.

A still further object of the present invention is to provide a pneumatic ejector having an expandable metal bellows wherein the ejecting force is continually supplied to the weapon when in the suspended condition, the release and ejection of the weapon taking place immediately upon removal of the suspension means thereby requiring no criticality of timing sequence.

Various other objects and advantages will appear from the following description of one embodiment of the invention and the novel features will be particularly pointed out hereinafter in connection with the appended claims.

In the drawings:

FIG 1 illustrates a vertical cross-sectional view of the pneumatic energy cartridge of the present invention and in the charged position prior to its placement upon a store or weapon to be ejected.

FIG. 2 pictorially illustrates the energy cartridge, with certain portions removed, engaging the store or Weapon prior to the ejection thereof, and

FIG. 3 illustrates the cartridge, with certain portions broken away, ejecting the store or weapon.

Referring now to FIG. 1 which illustrates the energy cartridge generally indicated as 10 in the charged position, there is shown a housing 11 of a lightweight, strong material, such as aluminum or the like, which has a removable cap, not shown, for permitting access to the units within the cartridge 10. Although not shown, it is understood that the housing 11 may be encapsulated with a lightweight cellural material such as polyurethane foam as a protective insulation for the energy cartridge. The housing 11 is divided into an upper compartment 13 which houses the actuating units for charging the energy cartridge and a lower compartment 14 for housing the bellows assembly to be described below. The two aforesaid compartments are separated by a supporting wall 16 which extends transverse to the longitudinal axis of the housing 11 and is integrally formed therewith.

Referring now to the structure found in the lower compartment 14, there is shown a bellows assembly generally noted at 20 which comprises an upper end fitting 21 secured about its periphery to a spring bellows 22 at one end thereof and further comprises a lower end fitting 23 rigidly secured to the bellows 22 at the other end thereof. Bellows 22 is formed of metal or other appropriate material such as stainless steel and has a predetermined compressed and expanded length which provides the bellows with a predetermined length of stroke. The lower end fitting 23 has a centrally located aperture 24 and includes a lower boss 25 extending therethrough, the shoulder 26 thereof abutting the lower end 3 fitting 23. Lower boss is internally threaded at 27 for engaging the bellows shaft MP to be discussed below and further includes an outwardly flared section 28 for facilitating the entrance of the bellows shaft 40 into the threaded section 27 of the boss 25.

A presser foot 3% formed of an elastic, incompressible and deformable material such as nylon, is bonded or otherwise secured to the lower end fitting 23 for thrust engagement with the store to be ejected. Presser foot 30 has a convex outer surface 31 so that as the pressure of the foot is exerted on the case of the weapon the nylon deforms and molds itself to the weapon and thereby provides an increased contact area. When the weapon is released, the anti-frictional properties of nylon permits the foot to slide along the weapon when it is ejected through its pitching travel arc. Since the nylon pad is interposed between the weapon and the metallic bellows it acts as a shock mitigation material. Finally, after the foot has ejected the weapon, the memory characteristic of nylon permits the material to return to its original shape for the next and possibly different application.

Continuing with a description of FIG. 1, a bellows shaft generally indicated at has the threaded end 41 thereof engaging the lower boss 25 for releasable connection thereto. Shaft 40 includes a longitudinally extending port 42 which taken together with cross port 43 permits pressure to be transmitted to the bellows interior through air charging valve 44 which is threadably received in a tapped portion 44 of port 42.

In order to preclude the pressure within the interior of the bellows from escaping through the area adjacent the shaft 40, a groove 45 is formed about the circumference of the shaft 40 for housing an O-ring 46. A pneumatic sleeve 48 is fitted about a portion of the shaft 49 and envelops the groove 45 with the O-ring 46 providing a seal therewith. A shoulder portion 49 of the pneumatic sleeve 48 abuts the periphery of an aperture 4-9 formed in the upper end fitting 21 and a flange portion 50 of the sleeve 48 is secured to an upper boss member 51 which in turn is secured to the upper end fitting 21.

The bellows assembly 20 heretofore discussed, is secured relative to the housing 11 by appropriate fastening means such as screw 55 threadably engaging the supporting wall 16 and the tap 52 formed in the upper boss 51.

Referring now to the upper compartment 13 of the energy cartridge 10 of FIG. 1, the bellows shaft 40 has a longitudinally extending key way 57 formed therein which is engaged by key 58 formed integrally with the index washer 60. By reason of the connection of index washer 60 to the supporting wall 16 by screw 55, the bellows shaft 40 is keyed to the housing and is thereby prevented from rotation with respect thereto. It is understood, of course, that although a single key way and key 57 and 58, respectively, are illustrated, an additional key way and key could be formed on shaft 40 and index washer 60 if so desired.

In order to take up the bellows shaft 40 relative to the housing ll-and thereby compress the bellows 22, a spur gear 70 including teeth 71 is threaded to the shaft 49. To permit rotation of the spur gear 70, a bearing assembly 72 is press fitted on the index washer 60 and is further held in position by a bearing retainer 73 which has the flange 74 thereof engaging the upper race of the bearing assembly 72. A shock mitigating ring 76, the purpose for which will be discussed below, of an elastic material, such as polyurethane, is dovetailed and held by a complementary slot 77 formed in the spur gear 70. The teeth 71 of spur gear 70 are engaged by complementary teeth on a broad face pinion gear 73 which enables the spur gear 70 to travel along the width of its face. Pinion gear 78 is driven by gear 79 on the reversible electric motor 80 engaging teeth 81 at the base of the pinion gear '78. Leads 82 extending from the motor 8t? allow the motor to be operated and to control the direction of operation thereof.

It can be readily seen from the above that when the motor is actuated in one direction the spur gear 70 will rotate about shaft 49 and as it is tightened against the bearing assembly 72 the shaft 40 will move upwardly and compress the bellows 2.2 to thereby bring the pressor foot 39 inside of the housing 11.

The energy cartridge 1%) may then be inserted into a receiving socket of a suspension system, not shown, and placed against the weapon or store to be ejected. This arrangement is adequately illustrated in PEG. 2 where the bomb or store $5 is retained on the airborne carrier 86 by releasable straps 87 or the like. At this time, the spur gear 70 is backed off by reversing the motor 80. Retaining ring 83 is provided at the upper portion of bellows shaft 449 to limit the upward travel of the spur gear 76 and it is understood that limit switches may be provided at this location to additionally stop the motor. The energy cartridge 10 is illustrated with the presser foot 30, shown exaggerated, engaging the store on the upper surface thereof. The spur gear 7% has been backed off a predetermined distance which will dictate the length of stroke applied to the store 85. It is understood that as the spur gear 70 is backed off there is a transfer of force from the compressed bellows 22 through presser foot 30 to the store and upon release of the bands 87, as shown in FIG. 3, the bellows will expand causing the bellows shaft 40 and associated spur gear 70 to move downwardly until arrested by the engagement of the shock mitigating ring 76 and the upper race of a bearing assembly 65. It is readily seen that the shock mitigating ring 76 provides a gradual deceleration of the spur gear 70 as the same travels downwardly and thereby avoids any sudden shock forces which might arise by a more sudden or abrupt stopping of the spur gear 7%.

Referring again to FIG. 1, after the energy cell 10 has been primarily charged by compression of the spring bellows 22 and prior to its attachment to the airborne carrier the bellows may be additionally charged to a predetermined amount by introducing pressurized air into the air charge valve 44 which then enters the bellows assembly 20 through cross port 43. It is understood that the secondary charging may take place upon the airborne carrier by a source of supply carried therewith. In order to maintain the aforesaid predetermined pressure within the bellows assembly 20 from the time of charging until the time of release of the store, a pressure sensing capsule 9b of construction well known in the art is secured to the housing 11 with the sensing portion thereof extending within the interior of the bellows assembly 20. The pressure sensing capsule 90 is of the type which actuates an on-off snap switch, not shown, which in turn controls a heating element through leads 96. The heating element 95 is secured to the housing 11 and has connection to a source of electrical supply also not shown. It is understood that should the pressure within the bellows assembly 20 fall below the predetermined and preset pressure, the sensing capsule will actuate the heating element which in turn will heat the housing and contiguous bellows 22 and thereby increase the pressure of the air within the bellows assembly 20.

It should be further noted that a wire-type switch arrangement may be provided in the presser foot so that the heating element will only be operable when the bellows is in the compressed position and when the presser foot is engaging the store. In this position the wire-like switches would be touching thereby closing the circuit and allowing the heater 95 to operate if actuated by the pressure sensing capsule 90. However, when the store has been ejected and the bellows expands thereby causing the pressure within the bellows assembly 20 to decrease, the wire switches would break contact due to the release of pressure on the presser foot and thereby preclude the heating element from operation notwithstanding the fact that the pressure sensing capsule indicates the decrease in pressure.

It is further understood that a thrust washer may be placed above the bearing assembly 72 to increase the bearing area upon which the shock mitigating ring engages thereby allowing a greater amout of flexible material to be used for purposes of mitigating shock.

Additionally, although the energy cartridge is illustrated as being charged by an electric motor in cooperation with spur gear 70, it is understood that the spur gear 70 may be replaced by a hand operated knurled knob which would thereby accomplish the same function manually.

Although the pneumatic energy cell has been described in conjunction with its use as a weapons ejector in a heli copter, it is understood that the present invention may be employed as a general utility energy cell where a large instantaneous pneumatic thrust force is desired.

It will be understood that various changes in the details, materials, steps and arrangements of parts, which have been herein described and illustrated in order to explain the nature of the invention, may be made by those skilled in the art within the principle and scope of the H invention as expressed in the appended claims.

What is claimed is:

1. An energy cell comprising:

a fixed housing,

corrugated means within said housing and being operable between an expanded position wherein an end portion of said corrugated means extends beyond the confines of said housing and a compressed position wherein said end portion is substantially flush with the outer confines of said housing,

and actuator means interconnected with said end portion for compressing said corrugated means and for c?ntrolling the extent of subsequent expansion there- 0 2. The energy cell of claim 1 wherein said corrugated means comprises:

a metallic pressure chamber having corrugated side walls and an end wall having operative connection with said actuator means,

and valve means associated with said chamber for permitting pressurization of said chamber.

3. The energy cell of claim 2 wherein:

said metallic pressure chamber includes an end wall,

and a presser foot constructed of an elastic, incompressible and deformable material secured to said end wall and extending beyond the confines of said housing when said chamber is in the expanded position.

4. The pneumatic energy cell of claim 3 wherein:

said means for maintaining the pressure within said chamber at some predetermined value comprises a pressure sensing capsule extending into said chamber,

and heating means connected to said capsule and being in contact with said housing for heating the same and said pressure chamber to thereby increase the pressure thereof, said heating means being operative only when said chamber is in said compressed position.

5. An energy cell comprising:

a housing,

a metallic bellows within said housing and being operable between an expanded position wherein a portion of said bellows extends beyond the confines of said housing with a compressed position wherein said bellows is subtantially flush with the outer confines of said housing,

said bellows having an end wall,

a threaded shaft secured to said end wall and extending outwardly beyond the confines of said bellows,

rotatable means threaded on said shaft and positionable on said shaft for abutment with said housing whereby when said rotatable means is so positioned further rotation thereof will urge said shaft to move relative to said rotatable means and said housing and thereby compress said bellows.

6. An energy cell comprising:

a housing,

a metallic bellows within said housing and being operable between an expanded position wherein a portion of said bellows extends beyond the confines of said housing with a compressed position wherein said bellows is substantially flush with the outer confines of said housing,

said belows having an end wall,

a threaded hollow shaft secured at one end to said end wall and extending outwardly beyond the confines of said bellows,

rotatable means threaded on said shaft and positionable on said shaft for abutment with said housing whereby when said rotatable means is so positioned further rotation thereof will urge said shaft to move relative to said rotatable means and said housing and thereby compress said bellows,

valve means operatively secured to the other end of said shaft for introducing air under pressure int-o said bellows,

and reversible driving means connected to said rotatable means for moving the same relative tosaid shaft.

'7. The energy cell of claim 6 wherein said rotatable means comprises a spur gear.

8. The energy cell of claim 7 wherein said valve means is threaded into said hollow shaft,

and said reversible driving means includes a motor having gears associated therewith and engaging said spur gear.

9. An energy cell comprising:

a housing,

a metallic bellows within said housing and being operable between an expanded position wherein a portion of said bellows extends beyond the confines of said housing with a compressed position wherein said bellows is substantially flush with the outer confines of said housing,

said bellows having an end wall,

a presser foot constructed of an elastic, incompressible, and deformable material secured to said end wall and having a convex face extending beyond the confines of said housing when said bellows is in the expanded position,

a threaded hollow shaft secured at one end to said end wall and extending outwardly beyond the confines of said bellows,

rotatable means threaded on said shaft and positionable on said shaft for abutment with said housing whereby when said rotatable means is so positioned further rotation thereof will urge said shaft to move relative to said rotatable means and said housing and thereby compress said bellows,

valve means operatively secured to the other end of said shaft for introducing air under pressure into said bellows,

and reversible driving means connected to said rotatable means for moving the same relative to said shaft.

10. An energy cell comprising:

a housing,

a metallic bellows within said housing and being operable between an expanded position wherein a portion of said bellows extends beyond the confines of said housing with a compressed position wherein said bellows is substantially flush with the outer confines of said housing,

said bellows having an end wall,

a threaded hollow shaft secured at one end to said end wall and extending outwardly beyond the confines of said bellows,

means interposed between said housing and said shaft for precluding rotation of said shaft,

rotatable means threaded on said shaft and positionable on said shaft for abutment with said housing whereby when said rotatable means is so positioned further rotation thereof will urge said shaft to move relative to said rotatable means and said housing and thereby compress said bellows,

valve means operatively secured to the other end of said shaft for introducing air under pressure into said bellows,

and reversible driving means connected to said rotatable means for moving the same relative to said shaft.

11. The energy cell of claim 10 wherein said means for precluding rotation of said shaft includes a longitudinally extending keyway formed on said shaft,

and a keying member secured to said housing and engaging said keyway.

12. An energy cell comprising:

a housing,

a metallic bellows within said housing and being operable between an expanded posit-ion wherein a portion of said bellows extends beyond the confines of said housing with a compressed position wherein said bellows is substantially flush with the outer confines of said housing,

said bellows having an end wall,

a pr-esser foot constructed of an elastic, incompressible, and deformable material secured to said end wall and having a convex face extending beyond the confines of said housing when said bellows is in the expanded position,

a threaded hollow shaft secured at one end to said end wall and extending outwardly beyond the confines of said bellows, the portion of said shaft within said bellows having a groove about the periphery thereof and an O-ring within said groove,

a sleeve member surrounding said shaft at the location of said groove and secured to said housing,

rotatable means threaded on said shaft and positionable on said shaft for abutment with said housing whereby when said rotatable means is so positioned further rotation thereof will urge said shaft to move relative to said rotatable means and said housing and thereby compress said bellows,

a bearing assembly interposed between said rotatable means and said housing for facilitating the rotation of said rotatable means,

valve means operatively secured to the other end of said shaft for introducing air under pressure into said bellows,

and reversible driving means connected to said rotatable means for moving the same relative to said shaft.

References Cited by the Examiner UNITED STATES PATENTS 1,479,282 1/1924 Burns 267-65 RICHARD C. PINKHAM, Primary Examiner. 

1. AN ENERGY CELL COMPRISING: A FIXED HOUSING, CORRUGATED MEANS WITHIN SAID HOUSING AND BEING OPERABLE BETWEEN AN EXPANDED POSITION WHEREIN AN END PORTION OF SAID CORRUGATED MEANS EXTENDS BEYOND THE CONFINES OF SAID HOUSING AND A COMPRESSED POSITION WHEREIN SAID END PORTION IS SUBSTANTIALLY FLUSH WITH THE OUTER CONFINES OF SAID HOUSING, AND ACTUATOR MEANS INTERCONNECTED WITH SAID END PORTION FOR COMPRESSING SAID CORRUGATED MEANS AND FOR CONTROLLING THE EXTENT OF SUBSEQUENT EXPANSION THEREOF. 